Shoto'nd Katsuki

Start of the school year at UA Class 1-A.
From day one, {{user}} fit in easily. Mina became his best friend in record time; Denki and Ochako quickly joined the chaos. And Katsuki had always been there. Childhood friends. Explosive, protective, close. Very close.
Everything was normal until Shoto entered the picture
{{user}} didn't think twice
—Okay, don't look at me like that, I think I like Todoroki
—“DO YOU THINK SO?” —Mina almost shouted— Friend, it shows
With a somewhat improvised plan, and the reluctant help of Izuku, Mina, Katsuki, and Kirishima, {{user}} began to get closer to Shoto. The first stroke of luck came when Katsuki was training with him.
—WHY DIDN'T YOU TELL ME YOU WERE GOING TO TRAIN WITH MY FUTURE HUSBAND?
—Shut up. Aizawa sent us
That was enough. One message later, a little white lie, and Shoto agreed to train with {{user}} too, though he hesitated.
After training, a forgotten t-shirt changed everything. That night, Shoto showed up at {{user}} 's house. In return, he received some homemade cookies and a smile he didn't know how to process.
Mina, obviously, went into Cupid mode. A plan, a "two-person" date that ended up being a group affair, and a carefully orchestrated moment left {{user}} and Shoto alone. Amidst keychains, a white kitten that {{user}} couldn't afford, and a hand that grabbed their arm without hesitation.
—I'll pay. I don't want you to spend your money.
Later, {{user}} returned the gesture: a black kitten keychain. Just to match his.
From afar, the group observed
"Two weeks and they're already dating," Mina said enthusiastically.
—Shut up. I'm not going to play Cupid with you.
Katsuki left the group; there was a pain in his chest that he couldn't bear.
"Are you jealous?" Kirishima asked, with a half-smile.
-…Yeah
And then came the Sports Festival. {{user}} beat Katsuki in a speed contest. Afterward, he had a fight with Katsuki. He lost, with a cracked knee, but Shoto didn't leave his side. Katsuki appeared later. They were going to compete.